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Insights into a viral motor: the structure of the HK97 packaging termination assembly.
Hawkins, Dorothy E D P; Bayfield, Oliver W; Fung, Herman K H; Grba, Daniel N; Huet, Alexis; Conway, James F; Antson, Alfred A.
Afiliación
  • Hawkins DEDP; York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK.
  • Bayfield OW; York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK.
  • Fung HKH; Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117Heidelberg, Germany.
  • Grba DN; MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK.
  • Huet A; Department of Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA.
  • Conway JF; Department of Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA.
  • Antson AA; York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK.
Nucleic Acids Res ; 51(13): 7025-7035, 2023 07 21.
Article en En | MEDLINE | ID: mdl-37293963
Double-stranded DNA viruses utilise machinery, made of terminase proteins, to package viral DNA into the capsid. For cos bacteriophage, a defined signal, recognised by small terminase, flanks each genome unit. Here we present the first structural data for a cos virus DNA packaging motor, assembled from the bacteriophage HK97 terminase proteins, procapsids encompassing the portal protein, and DNA containing a cos site. The cryo-EM structure is consistent with the packaging termination state adopted after DNA cleavage, with DNA density within the large terminase assembly ending abruptly at the portal protein entrance. Retention of the large terminase complex after cleavage of the short DNA substrate suggests that motor dissociation from the capsid requires headful pressure, in common with pac viruses. Interestingly, the clip domain of the 12-subunit portal protein does not adhere to C12 symmetry, indicating asymmetry induced by binding of the large terminase/DNA. The motor assembly is also highly asymmetric, showing a ring of 5 large terminase monomers, tilted against the portal. Variable degrees of extension between N- and C-terminal domains of individual subunits suggest a mechanism of DNA translocation driven by inter-domain contraction and relaxation.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Bacteriófagos / Ensamble de Virus Idioma: En Revista: Nucleic Acids Res Año: 2023 Tipo del documento: Article Pais de publicación: Reino Unido
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
Buscar en Google

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Bacteriófagos / Ensamble de Virus Idioma: En Revista: Nucleic Acids Res Año: 2023 Tipo del documento: Article Pais de publicación: Reino Unido